The present invention relates to new benzylisoquinoline derivatives which have been shown to be effective as antiarrhythmic agents. The isoquinoline derivative papaverine has found use as a smooth muscle relaxant and antispasmodic. Its actions on the heart to depress conduction and irritability of the myocardium served as a basis for its clinical use in abrogating atrial and ventricular extrasystoles and ventricular arrhythmias, but doses required were also found to cause dangerous arrhythmias by depression of A-V and intraventricular conduction. Accordingly, this class of compound has not found effective application in this indication.
Drugs such as quinidine, procainamide, propanolol and diphenylhydantoin have found significant application as antiarrhythmics, as has particularly the local anesthetic lidocaine (2-diethylamino-2',6'-acetoxylidide) which has proved effective as an antiarrhythmic drug administered both intravenously and intramuscularly. The use of 1-(2',6'-dimethylphenoxy)-2-amino propane has also been studied. Other classes of known drugs which exhibit antiarrhythmic properties are the 2-amino tetralins, and also certain primary amino acylanilides which have shown effectiveness both on parenteral and oral administration.